There is a way to override material and geometry properties during file load process.
It could be used for debugging or decorative purposes. For example, during debugging you may want to turn materials to 'wireframe', or decorate it with Goraud shading which is not a reflected in data file. You can also make modification to geometry data.

To be able to make changes to loading process a number callback functions can be registered for Xc3Loarer instance: 'onCreateColorMaterial ' for color material , 'onCreateAssetMaterial' Asset material ( images, textures etc.. ) and 'onCreateGeometry' geometrical data.